The present invention relates generally to detecting peak signals, and more particularly to detecting such signals at high frequencies.
The operating frequencies of communication systems continue to rise, and engineering components for such communication systems raises a number of challenges. For example, many communication systems include one or more amplifiers to amplify a received signal. At very high bandwidths, for example, optical communication systems operating at frequencies greater than 10 Gigahertz (GHz) and above, various problems may arise. Such problems include the possibility of bandwidth degradation, power dissipation, and increased die area. More so, for a circuit in an amplifier to detect a loss of received signal over large bandwidths, an extremely large requirement on the dynamic range of such detection is needed. Such a loss of detection circuit also requires low loading so that it causes no degradation in an amplifier's bandwidth or gain.
Additionally, in such communication systems, a need exists to vary a threshold signal representative of a loss of signal threshold, as hysteresis is needed to differentiate between an assertion level and a deassertion level. Further, such a threshold level must be maintained over a wide range (i.e., as measured in decibels) and further must be maintained over varying process, temperature, and supply voltage conditions.
A need thus exists to detect peak signals and to vary threshold levels over a wide operating range.